US6012851A - Rolling bearing - Google Patents

Rolling bearing Download PDF

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Publication number
US6012851A
US6012851A US09/151,699 US15169998A US6012851A US 6012851 A US6012851 A US 6012851A US 15169998 A US15169998 A US 15169998A US 6012851 A US6012851 A US 6012851A
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United States
Prior art keywords
outer ring
circumferential surface
surface portion
volume
amount
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Expired - Fee Related
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US09/151,699
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English (en)
Inventor
Kiyoshi Hirakawa
Akio Aoki
Kanichiro Watanabe
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NSK Ltd
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NSK Ltd
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Assigned to NSK LTD. reassignment NSK LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: AOKI, AKIO, HIRAKAWA, KIYOSHI, WATANABE, KANICHIRO
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C13/00—Rolls, drums, discs, or the like; Bearings or mountings therefor

Definitions

  • the present invention relates to a rolling bearing provided with an outer ring having an outer circumferential surface which has been subjected to surface hardening and which comes in contact with other members so that the outer ring is used as a roll.
  • a steelworks or the like there is a number of equipments or instruments using rolling elements such as a sintering machine pallet roller, a backup roller in a Sendzimir rolling mill, a chain conveyor, and so on.
  • an outer ring of a bearing is used as a roll surface of a roller.
  • works of various materials and temperatures are worked, so that such an outer circumferential surface of an outer ring of a bearing which comes in direct contact with the works is apt to be damaged conspicuously. Therefore, the outer circumferential surface of the outer ring of the bearing is subjected to surface treatment so as to make the outer circumferential surface have a hardness not less than a predetermined level.
  • the present invention has been developed to solve the foregoing problems. It is an object of the present invention to provide a rolling bearing using an outer ring as a roll, wherein expansion in the radial direction of the outer ring due to plastic deformation is hardly caused, deformation due to decomposition of retained austenite is hardly caused, and the outer ring can be prevented from cracking.
  • a rolling bearing comprises a rolling element, an outer ring having an outer circumferential surface portion subjected to surface hardening and an inner circumferential surface portion acting as an orbit of the rolling element, the outer circumferential surface portion being in contact with other members so as to be used as a roll, and an inner ring having an outer circumferential surface portion acting as an orbit of the rolling element, wherein the hardness of a core portion of the outer ring is set to be in a range of from 500 to 650 both inclusive in terms of Vickers hardness (Hv)
  • FIG. 1 shows a partially cutaway and partially expanded sectional view illustrating a rolling bearing having an outer ring used as a roll;
  • FIG. 2 shows a view illustrating the outline of an outer ring roll testing machine
  • FIG. 3 shows a view illustrating the outline of an outer ring fatigue-cracking testing machine
  • FIG. 4 shows a graph showing the relationship between the hardness (Hv) of a core portion and the amount of outer diameter expansion (mm) of the outer ring;
  • FIG. 5 shows a graph showing the relationship between the amount of retained austenite (%) and the amount of warp (mm) of the outer ring;
  • FIG. 6 shows a graph showing the relationship between the hardness (Hv) and the amount of extension (%) of the core portion of the outer ring;
  • FIG. 7 shows a graph showing the relationship between the residual stress (Mpa) and the cracking life (1 ⁇ 10 5 hour) of the outer ring;
  • FIG. 8 shows a graph showing the relationship between the amount of retained austenite (%) and the life (1 ⁇ 10 6 hour) of the outer ring;
  • FIG. 9 shows a partially sectional view illustrating a bearing portion of a palette roller of a sintering machine
  • FIG. 10 shows a diagram illustrating the outline of a roller for a Sendzimir rolling mill.
  • FIG. 11 shows a partially sectional view illustrating a bearing portion of a chain conveyor.
  • the amount of expansion of the outer diameter of the outer ring becomes substantially zero when the hardness of a core portion of the outer ring is Hv 500 or more as shown in FIG. 4. Therefore, the hardness of the core portion of the outer ring is made to be Hv 500 or more.
  • the extension of the core portion is large when the hardness of the core portion of the outer ring is not more than Hv 650 as shown in FIG. 6. Therefore, the hardness of the core portion of the outer ring is made to be Hv 650 or less.
  • the amount of retained austenite in the outer circumferential surface portion of the outer ring is made to be not more than 10% by volume, more preferably, not more than 6% by volume.
  • the amount of warp of the outer ring becomes small sufficiently when the amount of retained austenite in the outer circumferential surface portion of the outer ring is not more than 10% by volume as shown in FIG. 5. It is therefore preferable that the amount of retained austenite in the outer circumferential surface portion of the outer ring is made to be not more than 10% by volume.
  • the amount of retained austenite in an inner circumferential surface portion (orbital surface portion) of the outer ring is set to be in a range of from 20% by volume to 50% by volume, more preferably, in a range of from 25% by volume to 40% by volume.
  • the life of the bearing becomes long when the amount of retained austenite in the inner circumferential surface portion (orbital surface portion) of the outer ring is set to be in a range of from 20% by volume to 50% by volume as shown in FIG. 8. It is therefore preferable that the amount of retained austenite in the inner circumferential surface portion (orbital surface portion) of the outer ring is set to be in this range.
  • the retained compressive stress of the inner circumferential surface portion (orbital surface portion) of the outer ring is made to be not less than 130 Mpa, more preferably, not less than 180 Mpa.
  • the cracking life of the outer ring becomes long when the retained compressive stress of the inner circumferential surface portion (orbital surface portion) of the outer ring is set to be not less than 130 Mpa as shown in FIG. 7. It is therefore preferable that the retained compressive stress of the inner circumferential surface portion (orbital surface portion) of the outer ring is made to be not less than 130 Mpa.
  • the amount of the retained austenite in the outer circumferential surface is made to be not more than 10% by volume (preferably, not more than 6% by volume), the amount of the retained austenite in the orbital surface is made to be in a range of from 20% by volume to 50% by volume, and the retained compressive stress is made to be not less than 130 Mpa.
  • the hardness of the core portion of the outer ring, the amount of the retained austenite in the outer circumferential surface portion of the outer ring, and the retained compressive stress in the inner circumferential surface portion of the outer ring are made to be in the above-mentioned numerical ranges respectively, various properties of the outer ring, such as the amount of expansion, the amount of warp, the extension of the core portion, and so on are improved more greatly, and the cracking life of the outer ring is prolonged on a large scale. Accordingly, the life of the bearing as a whole is prolonged on a large scale.
  • oil at a temperature of 150° C. which was not beyond the tempering temperature was supplied onto the inner circumferential surface (orbital surface) of the outer ring in order to cool the inner circumferential surface (orbital surface) of the outer ring. While the tempering of the inner circumferential surface (orbital surface) was prevented from proceeding by supplying such as cooling oil, the outer circumferential surface was tempered by use of induction heating to thereby reduce the amount of retained austenite in the outer circumferential surface of the outer ring to a predetermined value. The reason why oil at a temperature of 150° C.
  • FIG. 4 shows the results of measuring the amount of expansion (mm) of the outer diameter of the outer ring.
  • FIG. 5 shows the results of measuring the amount of warp (mm) of the outer ring. It was proved that the amount of expansion of the outer diameter became 0.05 mm or less with no problem in practical use as the increase of bearing clearance when the hardness of the core portion of the outer ring was Hv 500 or more, and the expansion of the outer ring was hardly caused when the hardness was Hv 530 or less.
  • the extension (%) of the core portion of the outer ring begins to decrease when the hardness of the core portion is not smaller than Hv 600.
  • the hardness was more than Hv 650, the extension decreased suddenly, so that the resistance to shock loading was reduced. It was therefore proved that the range of the hardness of the core portion of the outer ring in which the outer diameter of the outer ring did not expand, and the resistance to shock loading was not reduced, was in a range of from Hv 500 to Hv 650 (preferably, from Hv 530 to Hv 600).
  • the amount of warp (mm) of the outer ring was increased with the increase of the amount of retained austenite (% by volume) in the outer diameter surface.
  • the amount of warp up to 0.05 mm and the amount of retained austenite up to 10% by volume are allowed when suitable crowning is given to the roller 5
  • the amount of warp of the outer ring is preferably made to be not more than 0.03 mm
  • the amount of retained austenite is preferably made to be not more than 6% by volume.
  • the amount of retained austenite herein means an amount of retained austenite up to a half of the depth of a surface-hardened layer.
  • the cracking strength of the outer ring is proportional to the residual stress in the orbital surface portion of the outer ring, and the strength is regarded as sufficient on practical use if the residual compressive stress of 130 Mpa or more exists in the orbital surface portion.
  • the cracking strength shows a large value under the existence of the residual compressive stress of 180 Mpa or more. Therefore, the residual compressive stress of the orbital surface portion is more important than the hardness of the core portion in order to improve the fatigue-cracking strength of the outer ring.
  • the rolling life increased when the amount of retained austenite in the orbital surface portion of the outer ring was 20% by volume or more in a rolling life test under the condition that foreign matters were mixed. However, it was proved that the rolling life was lowered when the amount of retained austenite was more than 50% by volume because the hardness of the orbital surface portion was lowered.
  • a plurality of cylindrical rolling bearings 2 each having an outer ring 4 (an outer diameter of 200 mm, a width of 120 mm, and an orbital surface diameter of 150 mm) manufactured by the materials and heat treatment in Table 1 were used as test bearings (an inner diameter of 100 mm) shown in FIG. 1.
  • the test was performed under the conditions that a test load was 20 ton, a rotation speed was 500 rpm, a test temperature was 40° C., and lubricating oil of VG 60 was mixed with 300 ppm of iron powder having the hardness of Hv 540 and the average particle size of 100 ⁇ m.
  • the amount of expansion and the amount of warp of the outer diameter of the bearings 2 after 50 hours were measured. The results are shown in FIG. 4 and FIG. 5, respectively.
  • a ring having an outer diameter of 120 mm, an inner diameter of 96 mm, and a width of 25 mm manufactured by the materials and heat treatment in Table 1 was used as a specimen for an outer ring cracking test.
  • the test was performed until the outer ring 4 was cracked out by using a testing machine having load rollers 8 and 9 shown in FIG. 3, under the conditions of a test load of 3 ton, a rotation speed of 1,500 rpm, a test temperature of 40° C., and lubricating oil of VG 60. This result is shown in FIG. 7.
  • a rolling life test was performed, by using a thrust-type life testing machine described in "Special Steel Handbook", the first edition (edited by Denki Seiko Kenkyusho, Rikogakusha, May 25, 1969), pp. 0-12, and by using a disc TP having an outer diameter of 60 mm, and a thickness of 6 mm, and manufactured by the materials and heat treatment in Table 1.
  • FIG. 9 shows a bearing portion of a pallet roller 10 of a sintering machine.
  • the reference numeral 13 represents an inner ring; 14, an outer ring; and 15, a roller.
  • FIG. 10 schematically shows a roller of a Sendzimir rolling mill 20.
  • the reference numeral 21 represents a work roller; 22, 23 and 24, rolling bearings (not shown) according to the present invention, having the outer rings as rolls.
  • FIG. 11 shows a bearing portion of a chain conveyor 30.
  • the reference numeral 33 represents an inner ring; 34, an outer ring; and 35, a roller.
  • the hardness of a core portion of an outer ring used as a roll is made to be in a range of from not less than Hv 500 to not more than 650, a plastic deformation of the outer ring can be prevented.
  • the amount of retained austenite in an outer circumferential surface is made to be not more than 10% by volume, so that a warp of the outer ring can be prevented.
  • residual compressive stress not less than 130 Mpa is formed in an orbital surface of the outer ring so as to prolong the cracking life of the outer ring on a large scale.
  • retained austenite of not less than 20% by volume is formed in an inner circumferential surface of the outer ring so as to prolong the rolling life of the orbital surface of the outer ring on a large scale.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)
US09/151,699 1997-09-18 1998-09-11 Rolling bearing Expired - Fee Related US6012851A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP9-253724 1997-09-18
JP25372497A JP3656372B2 (ja) 1997-09-18 1997-09-18 転がり軸受

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030123769A1 (en) * 2001-11-29 2003-07-03 Ntn Corporation Bearing part, heat treatment method thereof, and rolling bearing
US6726728B2 (en) * 2000-06-15 2004-04-27 Koyo Seiko Co., Ltd. Rolling bearing
US20040079310A1 (en) * 2002-10-17 2004-04-29 Ntn Corporation Full-type rolling bearing and roller cam follower for engine
US6770152B1 (en) 1999-09-03 2004-08-03 Nsk Ltd. Rolling bearing
US20040170348A1 (en) * 2003-02-28 2004-09-02 Ntn Corporation Transmission component, method of manufacturing the same, and tapered roller bearing
US20040179761A1 (en) * 2003-03-14 2004-09-16 Ntn Corporation Bearing for alternator and bearing for pulley
US20040228561A1 (en) * 2003-02-28 2004-11-18 Kouichi Okugami Differential support structure, differential's component, method of manufacturing differential support structure, and method of manufacturing differential's component
US20050045247A1 (en) * 2003-08-29 2005-03-03 Ntn Corporation Bearing's component, heat treatment method thereof, heat treatment apparatus, and rolling bearing
US20050109308A1 (en) * 2003-03-13 2005-05-26 Tadatoshi Suzuki Support structure in crank mechanism and component constituting crank mechanism
US20060083455A1 (en) * 2004-10-13 2006-04-20 Koyo Seiko Co., Ltd. Rolling slide member
US20070034301A1 (en) * 2005-08-10 2007-02-15 Ntn Corporation Rolling-contact shaft with joint claw
US20070169850A1 (en) * 2004-01-15 2007-07-26 Chikara Ohki Rolling bearing and heat treatment method for steel
US7594762B2 (en) 2004-01-09 2009-09-29 Ntn Corporation Thrust needle roller bearing, support structure receiving thrust load of compressor for car air-conditioner, support structure receiving thrust load of automatic transmission, support structure for continuously variable transmission, and support structure receivin

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021100746A1 (ja) * 2019-11-22 2021-05-27 Ntn株式会社 軌道部材、転がり軸受、転がり軸受の軌道輪及び転がり軸受の軌道輪の製造方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4696581A (en) * 1985-12-03 1987-09-29 Ntn Toyo Bearing Co., Ltd. Rolling bearing
US4904094A (en) * 1987-08-25 1990-02-27 Nippon Seiko Kabushiki Kaisha Ball-and-roller bearing system
US5520987A (en) * 1993-07-23 1996-05-28 Nsk, Ltd. Rolling/sliding member
US5577846A (en) * 1992-03-30 1996-11-26 Koyo Seiko, Co., Ltd. Eccentric rolling bearing device

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1929531U (de) * 1965-08-09 1965-12-23 Elex Ag Lager fuer klopfwellen in elektrofiltern.
DE3851573T2 (de) * 1987-06-10 1995-03-23 Koyo Seiko Co Reibungsloses Lager und mit einem solchen Lager ausgerüsteter Fahrzeugalternator.
JP2870831B2 (ja) * 1989-07-31 1999-03-17 日本精工株式会社 転がり軸受
JP3351041B2 (ja) * 1993-02-26 2002-11-25 日本精工株式会社 転がり軸受
JP3593668B2 (ja) * 1994-06-21 2004-11-24 Ｎｔｎ株式会社 転がり軸受

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4696581A (en) * 1985-12-03 1987-09-29 Ntn Toyo Bearing Co., Ltd. Rolling bearing
US4904094A (en) * 1987-08-25 1990-02-27 Nippon Seiko Kabushiki Kaisha Ball-and-roller bearing system
US5577846A (en) * 1992-03-30 1996-11-26 Koyo Seiko, Co., Ltd. Eccentric rolling bearing device
US5520987A (en) * 1993-07-23 1996-05-28 Nsk, Ltd. Rolling/sliding member

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6770152B1 (en) 1999-09-03 2004-08-03 Nsk Ltd. Rolling bearing
US6726728B2 (en) * 2000-06-15 2004-04-27 Koyo Seiko Co., Ltd. Rolling bearing
US20050205163A1 (en) * 2001-11-29 2005-09-22 Ntn Corporation Bearing part, heat treatment method thereof, and rolling bearing
US8425690B2 (en) 2001-11-29 2013-04-23 Ntn Corporation Bearing part, heat treatment method thereof, and rolling bearing
US20030123769A1 (en) * 2001-11-29 2003-07-03 Ntn Corporation Bearing part, heat treatment method thereof, and rolling bearing
US7438477B2 (en) 2001-11-29 2008-10-21 Ntn Corporation Bearing part, heat treatment method thereof, and rolling bearing
US20040079310A1 (en) * 2002-10-17 2004-04-29 Ntn Corporation Full-type rolling bearing and roller cam follower for engine
US7490583B2 (en) * 2002-10-17 2009-02-17 Ntn Corporation Full-type rolling bearing and roller cam follower for engine
US7682087B2 (en) 2003-02-28 2010-03-23 Ntn Corporation Transmission component, method of manufacturing the same, and tapered roller bearing
US20040170348A1 (en) * 2003-02-28 2004-09-02 Ntn Corporation Transmission component, method of manufacturing the same, and tapered roller bearing
US7334943B2 (en) 2003-02-28 2008-02-26 Ntn Corporation Differential support structure, differential's component, method of manufacturing differential support structure, and method of manufacturing differential's component
US20040228561A1 (en) * 2003-02-28 2004-11-18 Kouichi Okugami Differential support structure, differential's component, method of manufacturing differential support structure, and method of manufacturing differential's component
US7147382B2 (en) * 2003-03-13 2006-12-12 Ntn Corporation Support structure in crank mechanism and component constituting crank mechanism
CN100400930C (zh) * 2003-03-13 2008-07-09 Ntn株式会社 在曲轴机构中的支承结构和构成曲轴机构的零件
US20050109308A1 (en) * 2003-03-13 2005-05-26 Tadatoshi Suzuki Support structure in crank mechanism and component constituting crank mechanism
US20040179761A1 (en) * 2003-03-14 2004-09-16 Ntn Corporation Bearing for alternator and bearing for pulley
US8783961B2 (en) 2003-03-14 2014-07-22 Ntn Corporation Bearing for alternator and bearing for pulley
US8333516B2 (en) 2003-03-14 2012-12-18 Ntn Corporation Bearing for alternator and bearing for pulley
US20100232735A1 (en) * 2003-03-14 2010-09-16 Ntn Corporation Bearing for alternator and bearing for pulley
US7744283B2 (en) 2003-03-14 2010-06-29 Ntn Corporation Bearing for alternator and bearing for pulley
US8002907B2 (en) 2003-08-29 2011-08-23 Ntn Corporation Bearing's component, heat treatment method thereof, heat treatment apparatus, and rolling bearing
US20050045247A1 (en) * 2003-08-29 2005-03-03 Ntn Corporation Bearing's component, heat treatment method thereof, heat treatment apparatus, and rolling bearing
US7594762B2 (en) 2004-01-09 2009-09-29 Ntn Corporation Thrust needle roller bearing, support structure receiving thrust load of compressor for car air-conditioner, support structure receiving thrust load of automatic transmission, support structure for continuously variable transmission, and support structure receivin
US7641742B2 (en) 2004-01-15 2010-01-05 Ntn Corporation Rolling bearing and heat treatment method for steel
US20070169850A1 (en) * 2004-01-15 2007-07-26 Chikara Ohki Rolling bearing and heat treatment method for steel
US7484890B2 (en) * 2004-10-13 2009-02-03 Koyo Seiko Co., Ltd. Rolling slide member
US20060083455A1 (en) * 2004-10-13 2006-04-20 Koyo Seiko Co., Ltd. Rolling slide member
US8066826B2 (en) 2005-08-10 2011-11-29 Ntn Corporation Rolling-contact shaft with joint claw
US20070034301A1 (en) * 2005-08-10 2007-02-15 Ntn Corporation Rolling-contact shaft with joint claw

Also Published As

Publication number Publication date
JP3656372B2 (ja) 2005-06-08
DE19842455A1 (de) 1999-04-08
JPH1193956A (ja) 1999-04-06
DE19842455C2 (de) 2002-08-14

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